Formant transitions in the fluent speech of Farsi-speaking people who stutter

PurposeSecond formant (F2) transitions can be used to infer attributes of articulatory transitions. This study compared formant transitions during fluent speech segments of Farsi (Persian) speaking people who stutter and normally fluent Farsi speakers.MethodsTen Iranian males who stutter and 10 normally fluent Iranian males participated. Sixteen different “CVt” tokens were embedded within the phrase “Begu CVt an”. Measures included overall F2 transition frequency extents, durations, and derived overall slopes, initial F2 transition slopes at 30 ms and 60 ms, and speaking rate.Results(1) Mean overall formant frequency extent was significantly greater in 14 of the 16 CVt tokens for the group of stuttering speakers. (2) Stuttering speakers exhibited significantly longer overall F2 transitions for all 16 tokens compared to the nonstuttering speakers. (3) The overall F2 slopes were similar between the two groups. (4) The stuttering speakers exhibited significantly greater initial F2 transition slopes (positive or negative) for five of the 16 tokens at 30 ms and six of the 16 tokens at 60 ms. (5) The stuttering group produced a slower syllable rate than the non-stuttering group.ConclusionsDuring perceptually fluent utterances, the stuttering speakers had greater F2 frequency extents during transitions, took longer to reach vowel steady state, exhibited some evidence of steeper slopes at the beginning of transitions, had overall similar F2 formant slopes, and had slower speaking rates compared to nonstuttering speakers. Findings support the notion of different speech motor timing strategies in stuttering speakers. Findings are likely to be independent of the language spoken.Educational objectives This study compares aspects of F2 formant transitions between 10 stuttering and 10 nonstuttering speakers. Readers will be able to describe: (a) characteristics of formant frequency as a specific acoustic feature used to infer speech movements in stuttering and nonstuttering speakers, (b) two methods of measuring second formant (F2) transitions: the visual criteria method and fixed time criteria method, (c) characteristics of F2 transitions in the fluent speech of stuttering speakers and how those characteristics appear to differ from normally fluent speakers, and (d) possible cross-linguistic effects on acoustic analyses of stuttering.     

Effects of different attention tasks on concurrent speech in adults who stutter and fluent controls

Purpose: Motor theories indicate that focusing attention on well-practiced movements interferes with skilled performance; however, specific forms of attention (alerting vs. orienting vs. executive control) associated with this effect are not well understood. The present study explored this question in relation to stuttering, and examined whether dual task conditions that engaged sustained attention or working memory (WM) affected speech fluency in different ways. We also considered whether fluency changes were associated with changes in speech rate and language.Methods: Nineteen adults who stutter (AWS) and 20 controls produced spontaneous speech under a baseline condition and two dual task conditions: one involving a sustained attention task, the other involving WM demands.Results: Both groups produced fewer stutter-like disfluencies under dual task relative to baseline conditions and this reduction did not differ between the two dual tasks (attention vs. WM). Speech rate and language variables, which were potentially influenced by attention conditions, were not affected by dual tasks in the same way as disfluencies, and appeared to be unassociated with fluency results.Conclusions: Findings indicate that atypical disfluencies decrease when attention is divided, even when secondary task demands are minimal, as they were in the sustained attention task. For simple secondary tasks, fluency changes do not appear to be a byproduct of slowed rate and are not accompanied by observable changes in language. These results demonstrate that simple manipulations of attention can induce measurable effects on aspects of speech production, and may be a useful tool for facilitating fluency in clinical intervention.     

Investigating speech motor practice and learning in people who stutter

In this exploratory study, we investigated whether or not people who stutter (PWS) show motor practice and learning changes similar to those of people who do not stutter (PNS). To this end, five PWS and five PNS repeated a set of non-words at two different rates (normal and fast) across three test sessions (T1, T2 on the same day and T3 on a separate day, at least 1 week apart). The results indicated that PWS and PNS may resemble each other on a number of performance variables (such as movement amplitude and duration), but they differ in terms of practice and learning on variables that relate to movement stability and strength of coordination patterns. These findings are interpreted in support of recent claims about speech motor skill limitations in PWS.

Educational objectives: The reader will be able to: (1) define oral articulatory changes associated with motor practice and learning and their measurement; (2) summarize findings from previous studies examining motor practice and learning in PWS; and (3) discuss hypotheses that could account for the present findings that suggest PWS and PNS differ in their speech motor learning abilities.     

Auditory feedback control in adults who stutter during metronome-paced speech I. Timing Perturbation

PurposeThis study determined whether adults who stutter (AWS) exhibit deficits in responding to an auditory feedback timing perturbation, and whether external timing cues, which increase fluency, attenuate any disruptions due to altered temporal auditory feedback.MethodsFifteen AWS and sixteen adults who do not stutter (ANS) read aloud a multisyllabic sentence either with normal pacing or with each syllable paced at the rate of a metronome. On random trials, an auditory feedback timing perturbation was applied, and timing responses were compared between groups and pacing conditions.ResultsBoth groups responded to the timing perturbation by delaying subsequent syllable boundaries, and there were no significant differences between groups in either pacing condition. Furthermore, no response differences were found between normally paced and metronome-paced conditions.ConclusionThese findings are interpreted as showing that 1) AWS respond normally to pure timing perturbations, and 2) metronome-paced speech has no effect on online speech timing control as assessed in the present experiment.     

Performance on phonological and grammatical awareness metalinguistic tasks by children who stutter and their fluent peers

This study was undertaken to examine the performance of 23 children who stutter (CWS) and 23 children who do not stutter (CWNS) on three metalinguistic tasks. These included two phonological awareness assessment procedures (The Lindamood Auditory Conceptualization Test (LAC) and a Phoneme Reversal Task) and one modified Grammar Judgments Task where syntactic and semantic appropriateness of sentences was evaluated. Differences between groups were significant for the grammar judgment task, where CWNS outperformed CWS in judging syntactically and semantically anomalous sentences. Group differences were not significant for the phonological awareness tasks. The results underscore the importance of examining metalinguistic abilities of CWS through a variety of tasks. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) recognize the relevance of examining metalinguistic abilities within the context of research on language-stuttering dynamics; and (2) identify measures of metalinguistic abilities that can be used to compare the performances of CWS and CWNS.     

The impact of threat and cognitive stress on speech motor control in people who stutter

PurposeIn the present study, an Emotional Stroop and Classical Stroop task were used to separate the effect of threat content and cognitive stress from the phonetic features of words on motor preparation and execution processes.MethodA group of 10 people who stutter (PWS) and 10 matched people who do not stutter (PNS) repeated colour names for threat content words and neutral words, as well as for traditional Stroop stimuli. Data collection included speech acoustics and movement data from upper lip and lower lip using 3D EMA.ResultsPWS in both tasks were slower to respond and showed smaller upper lip movement ranges than PNS. For the Emotional Stroop task only, PWS were found to show larger inter-lip phase differences compared to PNS. General threat words were executed with faster lower lip movements (larger range and shorter duration) in both groups, but only PWS showed a change in upper lip movements. For stutter specific threat words, both groups showed a more variable lip coordination pattern, but only PWS showed a delay in reaction time compared to neutral words. Individual stuttered words showed no effects. Both groups showed a classical Stroop interference effect in reaction time but no changes in motor variables.ConclusionThis study shows differential motor responses in PWS compared to controls for specific threat words. Cognitive stress was not found to affect stuttering individuals differently than controls or that its impact spreads to motor execution processes.Educational objectives: After reading this article, the reader will be able to: (1) discuss the importance of understanding how threat content influences speech motor control in people who stutter and non-stuttering speakers; (2) discuss the need to use tasks like the Emotional Stroop and Regular Stroop to separate phonetic (word-bound) based impact on fluency from other factors in people who stutter; and (3) describe the role of anxiety and cognitive stress on speech motor processes.     

Factors affecting occupational advice for speakers who do and do not stutter

Factors affecting perceptions of occupational suitability were examined for speakers who stutter and speakers who do not stutter. In Experiment 1, 58 adults who do not stutter heard one of two audio recordings (less severe stuttering, more severe stuttering) of a speaker who stuttered. Participants rated the speaker's communicative functioning, personal attributes, and suitability for 32 occupations, along with perceptions of the occupations' speaking demands and educational requirements. Perceived speaking demand strongly affected occupational suitability ratings at both levels of stuttering severity. In Experiment 2, 58 additional adults who do not stutter heard a recording of another adult in one of two conditions (fluent speech, pseudo-stuttering), and provided the same ratings as in Experiment 1. In the pseudo-stuttering condition, participants' perceptions of occupational speaking demand again had a strong effect on occupational suitability ratings. In the fluent condition, suitability ratings were affected primarily by perceived educational demand; perceived speaking demand was of secondary importance. Across all participants in Experiment 2, occupational suitability ratings were associated with ratings of the speaker's personal attributes and communicative functioning. In both experiments, speakers who stuttered received lower suitability ratings for high speaking demand occupations than for low speaking demand occupations. Ratings for many high speaking occupations, however, fell just below the midpoint of the occupational suitability scale, suggesting that participants viewed these occupations as less appropriate, but not necessarily inappropriate, for people who stutter. Overall, the findings support the hypothesis that people who stutter may face occupational stereotyping and/or role entrapment in work settings. EDUCATIONAL OBJECTIVES: At the end of this activity the reader will be able to (a) summarize main findings on research related to the work-related experiences of people who stutter, (b) describe factors that affect perceptions of which occupations are best suited for speakers who stutter and speakers who do not stutter, and (c) discuss how findings from the present study relate to previous findings on occupational advice for people who stutter.     

A speech and psychological profile of treatment-seeking adolescents who stutter

PurposeThe purpose of this study was to evaluate the relationship between stuttering severity, psychological functioning, and overall impact of stuttering, in a large sample of adolescents who stutter.MethodParticipants were 102 adolescents (11–17 years) seeking speech treatment for stuttering, including 86 boys and 16 girls, classified into younger (11–14 years, n = 57) and older (15–17 years, n = 45) adolescents. Linear regression models were used to evaluate the relationship between speech and psychological variables and overall impact of stuttering.ResultsThe impact of stuttering during adolescence is influenced by a complex interplay of speech and psychological variables. Anxiety and depression scores fell within normal limits. However, higher self-reported stuttering severity predicted higher anxiety and internalizing problems. Boys reported externalizing problems—aggression, rule-breaking—in the clinical range, and girls reported total problems in the borderline-clinical range. Overall, higher scores on measures of anxiety, stuttering severity, and speech dissatisfaction predicted a more negative overall impact of stuttering.ConclusionTo our knowledge, this is the largest cohort study of adolescents who stutter. Higher stuttering severity, speech dissatisfaction, and anxiety predicted a more negative overall impact of stuttering, indicating the importance of carefully managing the speech and psychological needs of adolescents who stutter. Further research is needed to understand the relationship between stuttering and externalizing problems for adolescent boys who stutter.     

Phonological encoding in the silent speech of persons who stutter

The purpose of the present study was to investigate the role of phonological encoding in the silent speech of persons who stutter (PWS) and persons who do not stutter (PNS). Participants were 10 PWS (M=30.4 years, S.D.=7.8), matched in age, gender, and handedness with 11 PNS (M=30.1 years, S.D.=7.8). Each participant performed five tasks: a familiarization task, an overt picture naming task, a task of self-monitoring target phonemes during concurrent silent picture naming, a task of monitoring target pure tones in aurally presented tonal sequences, and a simple motor task requiring finger button clicks in response to an auditory tone. Results indicated that PWS were significantly slower in phoneme monitoring compared to PNS. No significant between-group differences were present for response speed during the auditory monitoring, picture naming or simple motor tasks, nor did the two groups differ for percent errors in any of the experimental tasks. The findings were interpreted to suggest a specific deficiency at the level of phonological monitoring, rather than a general monitoring, reaction time or auditory monitoring deficit in PWS. Educational objectives: As a result of this activity, the participant should: (1) identify and assess the literature on phonological encoding skills in PWS, (2) enumerate and evaluate some major psycholinguistic theories of stuttering, and (3) describe the mechanism by which defective phonological encoding can disrupt fluent speech production.     

Preverbal error-monitoring in stutterers and fluent speakers

This study was designed to characterize the brain system that monitors speech in people who stutter and matched controls. We measured two electrophysiological peaks associated with action-monitoring: the error-related negativity (ERN) and the error positivity (Pe). Both the ERN and Pe were reliably observed after errors in a rhyming task and a nonverbal flanker task, replicating previous reports of a language-monitoring ERN and demonstrating that the Pe can also be elicited by phonological errors. In the rhyming task, stutterers showed a heightened ERN peak regardless of whether they actually committed an error. Similar results, though only marginally significant, were obtained from the flanker task. These results support the vicious cycle hypothesis, which posits that stuttering results from over-monitoring the speech plan. The elevation of the ERN in stutterers and the similarity of the results between the flanker and rhyming tasks implies that speech-monitoring may rely on the same neural substrate as action-monitoring.     

Cognitive control of action naming in adults who stutter

PurposeBased on previous evidence that cognitive control of lexical selection in object (noun) naming operates differently in adults who stutter (AWS) versus typically-fluent adults (TFA), the aim was to investigate cognitive control of lexical selection in action (verb) naming in AWS.Method12 AWS and 12 TFA named line drawings depicting actions using verbs. Half of the pictures had high-agreement action names and the other half low-agreement action names. Naming accuracy and reaction times (RT), and event-related potentials (ERPs) time-locked to picture onset, were compared between groups.ResultsNaming RTs were slower for low- versus high-agreement trials, and the magnitude of this effect was larger in AWS versus TFA. Delta-plot analysis of naming RTs revealed that individual differences in selective inhibition were associated with the agreement effect on naming RTs in AWS but not TFA. Action naming elicited frontal-central N2 activity in both agreement conditions in TFA but not AWS. Additionally, a later, posterior P3b component was affected by agreement in TFA only. In AWS, low-agreement action naming elicited frontal P3a activation.ConclusionsResults suggest that cognitive control of action name selection was qualitatively different between groups. In TFA, cognitive control of lexical selection in action naming involved nonselective inhibition, as well as more efficient working memory updating on high- versus low-agreement trials. In AWS, cognitive control of low-agreement action naming involved increased focal attention. Individual differences in selective inhibition may have moderated cognitive control of action naming in AWS.     

Recurrent involuntary imagery in people who stutter and people who do not stutter

Objective

To compare intrusive memories in groups of people who do (PWS), and who do not (PWNS), stutter.

Method

Twenty-one participants who stuttered and 21 matched controls were given a semi-structured interview which explored imagery in speaking situations. The data were analyzed using a Content Analysis approach. Other outcome measures were the Beck Anxiety Inventory, the Beck Depression Inventory, the Post Traumatic Stress Disorder, PTSD, Symptom Scale: Self-Report Version.

Results

Significantly more stuttering participants than control participants indicated both recurrent imagery and associated memories. Content Analysis revealed themes of disfluency, anxiety, negative social evaluation, self-focus and pressure to speak that were common to both groups’ reports. Additional themes of helplessness, shame, sadness and frustration were found only in the images and memories of the stuttering group. No group differences were evident for the number of sensory modalities involved in images and memories, or for ratings of their vividness or strength of associated emotions, or on self-reports of depression, anxiety and trauma.

Conclusions

Recurrent imagery about events in childhood is a potent factor in the memories of PWS. It is worth modifying interventions that have been successfully applied for treating social anxiety for use with people who stutter.Educational objectives: After reading this article, participants will be able to: (a) identify the role of intrusive memories in psychiatric disorders and stuttering; (b) investigate how DSM criteria can be employed with people who stutter; (c) employ anxiety instruments used for assessing psychiatric disorders for stuttering; (d) distinguish between the intrusive memories experienced by people who stutter, and people who do not stutter; (e) apply treatments for intrusive memories in psychiatric disorders to work with people who stutter.     

Temporal organization of syllables in paced and unpaced speech in children and adolescents who stutter

PurposeSpeaking with an external rhythm has a tremendous fluency-enhancing effect in people who stutter. The aim of the present study is to examine whether syllabic timing related to articulatory timing (c-center) would differ between children and adolescents who stutter and a matched control group in an unpaced vs. a paced condition.MethodsWe recorded 48 German-speaking children and adolescents who stutter and a matched control group reading monosyllabic words with and without a metronome (unpaced and paced condition). Analyses were conducted on four minimal pairs that differed in onset complexity (simple vs. complex). The following acoustic correlates of a c-center effect were analyzed: vowel and consonant compression, acoustic intervals (time from c-center, left-edge, and right-edge to an anchor-point), and relative standard deviations of these intervals.ResultsBoth groups show acoustic correlates of a c-center effect (consonant compression, vowel compression, c-center organization, and more stable c-center intervals), independently of condition. However, the group who stutters had a more pronounced consonant compression effect. The metronome did not significantly affect syllabic organization but interval stability improved in the paced condition in both groups.ConclusionChildren and adolescents who stutter and matched controls have a similar syllable organization, related to articulatory timing, regardless of paced or unpaced speech. However, consonant onset timing differs between the group who stutters and the control group; this is a promising basis for conducting an articulatory study in which articulatory (gestural) timing can be examined in more detail.     

Acceptance and Commitment Therapy for adults who stutter: Psychosocial adjustment and speech fluency

The aim of the present study was to assess the effectiveness of an Acceptance and Commitment Therapy group intervention program for adults who stutter (N = 20). The program consisted of 2-h therapeutic sessions conducted weekly for eight consecutive weeks. It was an integrated program designed to improve: (a) psychosocial functioning, (b) readiness for therapy and change, (c) utilisation of mindfulness skills and psychological flexibility, and (d) frequency of stuttering. The findings provide innovative evidence for Acceptance and Commitment Therapy as an effective intervention with statistically significant improvements in psychosocial functioning, preparation for change and therapy, utilisation of mindfulness skills, and overall speech fluency. Follow-up data collected at three months post-treatment revealed that therapeutic gains were successfully maintained over time. These findings enhance the understanding of the impact of stuttering on psychological wellbeing and offer a new perspective on what might constitute successful stuttering treatment. Further, clinical research support is provided for Acceptance and Commitment Therapy delivered in a group format as a promising and novel intervention for adults who stutter.Educational objectives: The reader will be able to: (a) appreciate the potential for Acceptance and Commitment Therapy for adults who stutter; (b) identify the improvements participants experienced in psychosocial functioning and frequency of stuttered speech; (c) appreciate the six core processes of Acceptance and Commitment Therapy; and (d) appreciate the differences between an ACT model of intervention for adults who stutter compared to a CBT approach.     

Effect of word phonetic properties on stuttering anticipation and speech production in adults who stutter

PurposeStuttering anticipation is a significant factor in an individual’s stuttering experience. People who stutter have reported words and sounds that they anticipate stuttering on. Attempts at understanding the association between stuttering anticipation and stuttering outcomes and the impact of phonetic properties on stuttering anticipation and overt stuttering have been insufficiently examined. This study aims to address these important issues.MethodsData were collected as part of a larger brain imaging study. Twenty adults who stutter rated a 414 word-list on stuttering anticipation. Participant-specific ‘high’ and ‘low’ anticipated words were selected. Twelve of the 20 participants returned for a second session 2–11 weeks later, during which they read the selected words again and stuttering occurrence was recorded.ResultsAmong the 20 participants, three sub-groups with “high” (N = 6), “moderate” (N = 5) and “low” (N = 9) stuttering anticipation were identified. Significant “high stuttering” anticipation was found on consonants, plosives, bilabials and alveolars, as well as labials and coronals. In 5 of the 8 participants who stuttered during session 2, more than 80 % of words stuttered were previously rated with high anticipation. Consonants, plosives, bilabials and alveolars, and labials and coronals were the most frequently stuttered (>27 %).ConclusionWhile not all adults who stutter demonstrate high word-specific stuttering anticipation, we found that more than half anticipated this to a high degree. Furthermore, both word-specific phonetic properties and stuttering anticipation impact stuttering occurrence. The inclusion of word-specific stuttering anticipation ratings may increase the likelihood of stuttering in experimental studies and improve treatment outcomes through individualized intervention.     

The role of temporal speech cues in facilitating the fluency of adults who stutter

PurposeAdults who stutter speak more fluently during choral speech contexts than they do during solo speech contexts. The underlying mechanisms for this effect remain unclear, however. In this study, we examined the extent to which the choral speech effect depended on presentation of intact temporal speech cues. We also examined whether speakers who stutter followed choral signals more closely than typical speakers did.Method8 adults who stuttered and 8 adults who did not stutter read 60 sentences aloud during a solo speaking condition and three choral speaking conditions (240 total sentences), two of which featured either temporally altered or indeterminate word duration patterns. Effects of these manipulations on speech fluency, rate, and temporal entrainment with the choral speech signal were assessed.ResultsAdults who stutter spoke more fluently in all choral speaking conditions than they did when speaking solo. They also spoke slower and exhibited closer temporal entrainment with the choral signal during the mid- to late-stages of sentence production than the adults who did not stutter. Both groups entrained more closely with unaltered choral signals than they did with altered choral signals.ConclusionsFindings suggest that adults who stutter make greater use of speech-related information in choral signals when talking than adults with typical fluency do. The presence of fluency facilitation during temporally altered choral speech and conversation babble, however, suggests that temporal/gestural cueing alone cannot account for fluency facilitation in speakers who stutter. Other potential fluency enhancing mechanisms are discussed.Educational Objectives: The reader will be able to (a) summarize competing views on stuttering as a speech timing disorder, (b) describe the extent to which adults who stutter depend on an accurate rendering of temporal information in order to benefit from choral speech, and (c) discuss possible explanations for fluency facilitation in the presence of inaccurate or indeterminate temporal cues.     

Shame, self-consciousness, and locus of control in people who stutter

Stuttering is a multidimensional disorder, including psychological as well as physiological elements. This investigation of the value of 3 psychological constructs (shame, self-consciousness, and locus of control) in the prediction of 3 self-reported behavioral dimensions of stuttering (struggle, avoidance, and expectancy) revealed shame and self-consciousness to be significant psychological predictors of the selected dimensions of stuttering, whereas locus of control was found not to be. Certain demographic elements, including affiliations with others who stutter, were also determined to be predictive of the stuttering dimensions. The present findings and their implications for theory, research, and practice are discussed.